1. Field of the Invention
The present invention relates to a technology which allows for controlling error correction coding processing performed for data transmitted to a data receiving device based on the quality of transmitted data.
2. Description of the Related Art
In recent years, broadband has been increasingly used in the environment of the Internet due to the widespread use of Asynchronous Digital Subscriber Line (ADSL), Fiber To The Home (FTTH), etc. Further, the processing capabilities of various computing devices including a personal computer (PC) or the like have been significantly increased.
Against the background of the above-described communication environments and the data processing environments with increased capabilities, streaming technologies for distributing multimedia data including video data, sound data, and so forth in real time via a network have become available. Consequently, a user can view a broadband broadcast of a live medium and/or a recorded medium. Further, the user can view the contents of the recorded medium on an on-demand basis.
The quality of service (QoS) technologies assuring the communication speed, the delay time, the jitter amount, the packet loss rate, and so forth, have been used to provide services for which no delay nor suspension is allowed, such as the real time distribution of sound data and/or video data, a picture phone, and so forth.
For example, an error occurring on a network can be corrected through the use of communication-level error correction technologies including the forward error correction (FEC), etc. Further, if an error occurs in the case where MPEG-4 Video is used, the error can be concealed so that the error becomes unobtrusive.
Further, the packet transfer is executed by dynamically switching between the error control achieved through the FEC and that achieved based on retransmission request processing in accordance with the packet loss state and the error occurrence state of the network. Further, a method of increasing the error correction strength of the FEC, only performing the retransmission request processing without performing the FEC, etc. on the transmission side has been proposed (e.g., refer to Japanese Patent No. 03757857).
However, if redundant data is transmitted to correct an error when the error control is performed through the FEC, as in the past, the throughput of the network is decreased. Further, according to the data communication method disclosed in Japanese Patent No. 03757857, no consideration is given to the connection between the error concealment and the FEC. Therefore, final errors that were not corrected through the FEC are concealed through a video decoder, for example. Namely, errors have been separately controlled. Therefore, it has been difficult to achieve both the efficient use of communication bands and the retention of the video quality.